gnu: Add sfarkxtc.

* gnu/packages/compression.scm (sfarkxtc): New variable.

gnu: Add sfarklib.

* gnu/packages/compression.scm (sfarklib): New variable.

gnu: Add Guitarix.

* gnu/packages/audio.scm (guitarix): New variable.

gnu: ardour: Update to 4.1.

* gnu/packages/audio.scm (ardour): Update to 4.1.

gnu: Add libtar.

* gnu/packages/compression.scm (libtar): New variable.

Add Claes Wallin to 'AUTHORS'.

gnu: Add pv.

 * gnu/package/pv.scm (pv): New file.
 * gnu-system.am (GNU_SYSTEM_MODULES): Add it.

Signed-off-by: Alex Kost <alezost@gmail.com>

gnu: Refer to 'gcc' instead of 'gcc-4.9'.

* gnu/packages/commencement.scm (gcc-boot0, cross-gcc-wrapper,
  libstdc++, gcc-final): Refer to GCC instead of GCC-4.9.
* gnu/packages/cross-base.scm (%xgcc): New variable.
  (cross-gcc-arguments, cross-gcc): Refer to %XGCC instead of GCC-4.9.
* gnu/packages/llvm.scm (clang-from-llvm): Refer to GCC instead of GCC-4.9.
* gnu/packages/make-bootstrap.scm (package-with-relocatable-glibc,
  %gcc-static, %gcc-stripped): Likewise.

gnu: youtube-dl: Update to 2015.06.25.

* gnu/packages/video.scm (youtube-dl): Update to 2015.06.25.

gnu: Add python2-fastlmm.

* gnu/packages/python.scm (python2-fastlmm): New variable.

gnu: Add python2-pysnptools.

* gnu/packages/python.scm (python2-pysnptools): New variable.

emacs: Add 'guix-root-map'.

* emacs/guix-base.el (guix-define-buffer-type): Move common key bindings
  from here...
  (guix-root-map): ... to here.  New variable.
* emacs/guix-info.el (guix-info-mode-map): Use it.
* emacs/guix-list.el (guix-list-mode-map): Use it.
* doc/emacs.texi (Emacs Keymaps): Document it.

gnu: nettle: Disable ifunc method of library initialization.

* gnu/packages/nettle.scm (nettle)[arguments]: Add 'disable-ifunc-init-method'
  phase.

gnu: Replace versioned gfortran inputs with just "gfortran".

* gnu/packages/julia.scm (julia)[inputs]: Replace "gfortran-4.8" with
  "gfortran".
* gnu/packages/machine-learning.scm (randomjungle)[native-inputs]: Likewise.
* gnu/packages/maths.scm (arpack-ng, lapack, petsc, superlu)
   (superlu-dist, openblas, openspecfun, atlas)[inputs]: Likewise.
   (octave)[native-inputs]: Likewise.
   (gmsh)[propagated-inputs]: Likewise.
* gnu/packages/mpi.scm (openmpi)[inputs]: Likewise.
* gnu/packages/python.scm (python-numpy-bootstrap)[native-inputs]: Likewise.
* gnu/packages/python.scm (python-scipy)[native-inputs]: Likewise.
* gnu/packages/statistics.scm (r)[inputs]: Replace "gfortran-4.9" with
  "gfortran".

gnu: Add default GCC and default gfortran.

* gnu/packages/gcc.scm (gcc): New variable.
* gnu/packages/gcc.scm (gfortran): New variable.

gnu: gstreamer: Add search path specification for 'GST_PLUGIN_SYSTEM_PATH'.

This reverts commit e53fc0c8a, which add it wrongly to gst-plugins-base.

* gnu/packages/gstreamer.scm (gstreamer)[native-search-paths]: New field.
  (gst-plugins-base)[native-search-paths]: Remove.

import: pypi: Detect inputs.

* guix/import/pypi.scm (python->package-name, maybe-inputs, compute-inputs,
  guess-requirements): New procedures.
* guix/import/pypi.scm (guix-hash-url): Now takes a filename instead of an
  URL as input.
* guix/import/pypi.scm (make-pypi-sexp): Now tries to generate the inputs
  automagically.
* tests/pypi.scm: Update the test.

linux-initrd: Produce cpio archives with zeroed timestamps, etc.

* guix/cpio.scm (file->cpio-header*): New procedure.
* gnu/build/linux-initrd.scm (write-cpio-archive): Add #:file->header argument
  to 'cpio:write-cpio-archive'.

linux-initrd: Populate cpio archives in a deterministic order.

* gnu/build/linux-initrd.scm (write-cpio-archive)[files]: Use 'sort' instead
  of 'reverse'.

linux-initrd: Use (guix cpio) instead of GNU cpio.

* gnu/build/linux-initrd.scm (write-cpio-archive): Remove 'open-pipe*' and
  related calls.  Compute list of files in 'files' variable.  Use
  'cpio:write-cpio-archive'.  Remove #:cpio parameter.
  (build-initrd): Remove #:cpio parameter.
* gnu/system/linux-initrd.scm (expression->initrd): Likewise, and adjust
  BUILDER accordingly.  Add (guix cpio) to #:modules.